The combination of fast, non-destructive, and surface-sensitive spectroscopic methods, surface photovoltage technique (SPV), spectroscopic ellipsometry in the ultraviolet and visible region (UV-VIS-SE), and Fourier-transform infrared ellipsometry (FTIR SE) provide detailed information about the influence of surface microroughness and the hydrogen and oxide coverage on electronic properties of H-terminated and oxidized silicon interfaces during the wet-chemical preparation process. By systematic investigations of common and newly developed wet-chemical preparation methods, correlations were established between the preparation-induced surface morphology, the resulting interface charge, the density, and energetic distributions of interface states. It was shown that the efficiency of passivation on wet-chemically treated Si (1 1 1) and Si (1 0 0) interfaces and the stability of H-termination in clean-room atmosphere strongly depends on the remaining surface microroughness and initial interface state density. (C) 2004 Elsevier B.V. All rights reserved.